[linux-lvm] Which lvm2 code branches are important?

[Gang He]

Hello List,

After you clone the code from git://sourceware.org/git/lvm2.git, you can find lots of remote code branches.
But which code branches are important for the third party users/ developer? That means we should monitor these code branches.
For example, 
Which code branches are main (or long-active) code branches?
Which code branches are used for which lvm2 products (big versions)?
What are the main differences between different lvm2 products? E.g. some features are added/removed.


Thanks a lot.
Gang